Pile-driving read



Jan. 16, 1934. R. D. BUDD 1,943,420

FILE DRIVING HEAD Filed Aug. 5, 1930 dig/105N701? B Y j A TTOR/VEVPatented Jan. 16, F334 willie i A i it PILE-DREVING HEAD ApplicationAugust 5, 1930.

6 Claims.

The invention relates to the driving of pipe piles or sh t piling, andthe subject of the invention is an improvement in driving heads whichare placed on the pile to receive the blows of the steam or drop hammer.

In the driving of pipe piles much diificulty is experienced fromdistortion of the pile. This commonly takes the form of a bulging out ofthe wall mediately below the upper end, in addition to which he upperend may contract so as to lock the d ing head against removal. Three orfour lengths of ipe may be needed to make up a pile, the lengths beingadded successively and being coupled by means of sleeves, in which thepipe ends are required to have a fairly close fit. It becomes necessary,therefore, to cut off distorted ends of the pipes, and to cut them awayfrom the driving head if locking has occurred. This adds a special laborcost, not to mention the gases and equipment used for cutting, but amore serious loss is the very considerable delay in operations, with allthat that involves. There is also the waste or" material cut off, whichin the aggregate amounts to an item.

Some use has been made of driving heads containing a block of wood tosoften the blows, but this expedient is unsatisfactory because the woodburns out rapidly under the heat of impact, and because it is notpracticable to provide wood blocks which will afford just enoughcushioning to save the piles from distortion or which will remainadequate as the driving proceeds.

The purpose of this invention is to provide a shock-absorbing head forthe driving of metal piles, with which it is readily possible to havethe piles as undeformed after driving as at starting, without, on theother hand, absorbing any substantial amount of energy. The object isalso to provide the head with shock-absorbing means which will not burnout and which can be easily adjusted to meet requirements.

The driving head of this invention has a cup or recess in which acollection of discs is loosely placed, so that the blows must betransmitted through the layers. The shock-absorbing means consistsessentially of a series of steel discs about half an inch thick, more orless, separated by layers or discs of compressible, non-combustible, andnon-metallic material. The composition 01' the stack may be varied tosome extent.

50 However, the most effective and efiicient embodiment of theinvention, and one which is desirably compact, employs a combination ofstrong metal discs, more especially steel, associated with non-metallicdiscs or layers of compressible and non-combustible material. Materialof a fibrous Serial No. 473,189

nature is best for this purpose, and asbestos is especiallyadvantageous, though vulcanized fiber or the like may be employed if nottoo brittle. In a shock-absorbing head of this character there is notonly the possibility of slight movement between the discs but also thecompressibility of the fiber layers which are gradually compacted. Theeffect of the compacting layer or layers is not merely a cushioningaction but rather to develop slight localized distortion in the steeldiscs as the result of non-uniformity in the compacting layer causing itto support the steel layer unequally at different regions when the blowsare received.

The material of the compacting layers may have a tendency to pulverizeunder the hammering, in which event the puffs of air which are createdwhen the discs are forced together would blow the particles out of thehead. To avoid frequent eplacement of these discs I may employ one ormore discs of malleable meal, such as lead or even copper, to serve as apacking by flowing laterally and squeezing against the wall or therecess.

While the hammer might be so formed as to enter the cup and act directlyon the assemblage of discs, is much better to transmit the blows to therelatively thin discs through a heavy steel anvil resting in he cup ontop of the pile of discs and of sufficient height to project at alltimes above the head.

While the invention is referred to as a shockabsorbing head, it is to beunderstood that its function is to modify or control the eifect of theimpacts only in the sense of avoiding or minimizing distorition in thepipe being driven, it being equally important to preserve theeffectiveness of the hammer as a means for sinking the pipe into theground. The purpose, therefore, is not to dissipate the force of theblows but to eliminate the destructive effect of wasted energy whichordinarily produces distortion in the pipe.

The accompanying drawing, forming part hereof, shows a practicalembodiment of the driving head in sectional perspective.

The steel driving head proper 2 is preferably formed at the bottom witha plurality of portions 3 of reduced diameter to enter pipe piles ofdifferent sizes and to provide shoulders to rest on the upper end of thepipe. A cross hole 4 may be drilled through the solid part of the headto receive chain for connecting the head with the hammer to obviateunnecessary handling.

The upper part of the head is made with a cylindrical fia+-botton1edrecess 6 so that it is substantially like a cup. In the lower half, moreor less, of this recess the discs are placed. The drawing illustrates atypical assemblage which has been found satisfactory in practice, but itwill be understood that the number, materials and relative arrangementof the discs can be varied. As shown, there are three steel discs 7,each resting on a disc 8 of asbestos sheeting and having over it a leaddisc 9.

A short steel cylinder 11 is placed in the upper part of the cup,resting on the collection of discs and projecting sufficiently above thetop of the head so that it will continue to take the blows of the hammernotwithstanding decrease in thickness of the compressible layers.

Steel discs out from half-inch plate and asbestos discs having initiallysubstantially the same thickness have been used with good efiect,whereas the lead discs may be about one-eighth of an inch thick, but itwill be understood that these proportions are given merely by way ofillustration and are in no sense limiting.

It has been found that the heads could be used for about a week ofactive service without replacement of the compacting or packing discs,The asbeslos discs become gradually thinner as the result ofcompression, and at any sign of distortion in the pipe the collection ofdiscs should be removed and fresh asbestos discs should be put in. Thelead disc or discs also require renewing. To facilitate removal of thediscs a drive-out hole 10 may be drilled, extending from the bottom ofthe head to the center oi the bottom of the recess of the cup.

The desired effect of the shook-absorbing means is secured by varyingthe number of the discs, or by using more of one kind than or" another,in accordance with the size of the pile and the earth conditions.

I claim:

1. A pile-driving head comprising a head proper formed with a cup, saidhead proper adapted to rest on the upper end of a tubular pile totransmit the driving stress thereto, shock-absorbing means in said cupconsisting of a loose assemblage of steel discs separated by layers ofnonmetallic, non-combustible, compressible material, and an anvilresting on said assemblage.

2. A pile-driving head comprising a head proper resting on the upper endor" a tube to transmit the driving stress thereto and having a cupcavity, and shock-absorbing means in said cavity comprising a number ofsteel discs and interjacent discs of non-metallic, non-combustiblecompressible material.

3. A pile-driving head comprising a head proper resting on the upper endof a tube to transmit the driving stress thereto and having a cupcavity, and shock-absorbing means in said cavity comprising a looseassemblage of steel discs associated with interjacent discs ofnon-combustible fiber, together with one or more discs of soft metal toserve as a packing.

4. A head for driving steel tubes, said head comprising a head properresting on the upper end of the tube to transmit the driving stressthereto and having a cup cavity, and cushioning means in said cavitycomprised essentially of a series of steel discs and non-combustiblefiber discs separating the steel discs so as to develop slight localdistortion therein under the blows of the hammer, sufiicient to overcomebulging out of the upper part of the tube without substantial absorptionof energy.

5. A head for driving steel tubes, said head comprising a head properresting on the upper end of the tube to transmit the driving stressthereto and having a cup caviLy, and cushioning means in said cavitycomprised essentially of a series of steel discs separated by layers ofnoncombustible material which will compact nonuniformly.

6. A pile-driving head adapted to be applied to the upper end of a steeltube, said head comprising a head proper resting on the upper end of thetube to transmit the driving stress thereto and having a cup cavity,cushioning means in said cavity comprised essentially of a plurality jof steel discs alternating with non-combustible compacting layers, and asteel impact block resting on the discs and projecting above the cup.

ROBERT D. BUDD.

